.40 S&W Shield feed failures with JHP

[MoonclipMaster]

It's been perfectly reliable for years and thousands of rounds, but when I tried a new defense round recently - Federal Tactical HST 165 gr. .40 S&W - I kept getting this feed failure with the 7-round magazines:

(Note: that is a cartridge of Speer Gold Dot 180 gr. .40 S&W in the photo, but the feed failures with the Federal Tactical HST ammo looked exactly the same.).

I switched back to Speer Gold Dot 180 gr. .40 S&W (SKU 53962), which had always worked perfectly in both my Shield and fullsize S&W M&P. Nope, same problem with the Shield, as shown above.

With both kinds of ammo, it's always the second round in a 7-round magazine. That is, I shoot the one that's in the chamber from me racking/releasing the slide after loading the magazine, then the next round out of the magazine fails to feed as seen above.

It doesn't happen every time, but does happen a lot. Happens 1-handed, both left and right-handed, and even with 2-handed shooting.

Based on today's range trip, it might be particular to one of my three, 7-round magazines, but that may be happenstance. I do have that magazine labeled. On the previous trip, it seemed to be all 3 of my 7-round mags that were having the problem, but i only had the Federal ammo on that trip.

FWIW, both kinds of ammo (Federal Tactical HST and Speer Gold Dots) work fine in my .40 S&W M&P fullsize. That's based on shooting 5-6 full, 15-round magazines of both types of ammo in the fullsize M&P without a single failure.

Going back to the Shield again: I did try some FMJ ammo as well, a few 7-round magazines' worth of Winchester Ranger .40 S&W (Q-something SKU, I can track down the exact ammo type if it's important). No failures with FMJ, at least not so far.

What's going on here? Do I need new magazine springs?

 

[Tannhauser]

I would try changing magazine springs. If the Gild Dot 180 was working fine in the past, but suddenly isn’t, string indicator that the problem is something has changed with the magazine, which is usually indicates a spring Problem.

 

[rosewood]

I too have experienced this with my shield. Mine was with my own reloads (FMJs) and I considered I had seated the bullets too far out. Since I had already switched to another EDC, I haven't spent too much time chasing the rabbit. I did try some rounds seated deeper with the same bullets, and it didn't do it on the next range trip. I have several mags and I never spent the time to identify if one mag was the culprit or if others did it. I did buy a few of them used.

I do feel a stronger mag spring would likely fix the problem.

Rosewood

 

[MoonclipMaster]

Thanks for the feedback, folks.

Wolff Gunsprings to the rescue! I believe I'll replace all the springs, even in the 6-round magazines. Cheap insurance.

I'm going to go ahead and replace all the magazine springs plus the recoil spring on the fullsize M&P as well. I've had that gun forever, they're probably getting worn out anyway.

 

[Tannhauser]

Thanks for the feedback, folks.

Wolff Gunsprings to the rescue! I believe I'll replace all the springs, even in the 6-round magazines. Cheap insurance.

I'm going to go ahead and replace all the magazine springs plus the recoil spring on the fullsize M&P as well. I've had that gun forever, they're probably getting worn out anyway.

I buy Wolff springs by the 10 pack. I’ve bought many M&P police trade in mags of various flavors. Any tgst look well used I just swap out the springs. Before I started doing this I had several that immediately started producing failures like you’re showing. A stoning swap immediately cured the problem.

I would recommend marking/tracking your mags. I keep a tiny 3”x5” notebook in my range bag. Anytime a gun has an issue tgst might be mag related, I jot it down. Sometimes you can see a pattern. I had one 1911 mag that was always a problem. Follower swap snd soring swap did nothing. Eventually I just crushed the body and dumpstered it. Life is too short for crappy mags.

 

[MoonclipMaster]

Yep. I have all my other pistol and rifle mags numbered for just such reasons. I've been so spoiled by the Shield always working that I didn't bother. That'll change.

 

[gboling]

I have known that to happen if the magazine spring is installed wrong. Several years ago some magazines were shipped from the factory with the springs installed wrong causing that problem but I forgot which model that was.

 

[MoonclipMaster]

I have known that to happen if the magazine spring is installed wrong. Several years ago some magazines were shipped from the factory with the springs installed wrong causing that problem but I forgot which model that was.

That's amazing that this would slip by QC, but at the same time I can see it happening.

I got my Wolff springs yesterday, installed all of them today. I'm happy to report that the original springs were all installed correctly at least.

Can't get to the range just yet but I'm hoping the new springs will solve originally-stated problem.

 

[MoonclipMaster]

New magazine springs did the trick

Huzzah! It's fixed!

At least, it's as fixed as I can verify without running $200 worth of JHP's through it.

Since the feed failures were all happening on the 2nd round in a 7-round magazine, I loaded up all 3 of them with the Gold Dots and fired 2-3 rounds from each, then topped them back off. Did this 3-4 times with each magazine, also shot a couple to empty to make sure that worked too. Zero failures.

If the same problem from earlier were still present, I should have seen it.

For thoroughness I also tested the 6 round mags. They got new springs even though I hadn't had any failures yet. Turns out it's exactly the same spring, which is interesting.

I briefly thought that using the same spring in both, might explain why the 7 round mags showed failures first, but I'm not sure that makes sense. While the 7 round mags are taller than the 6 rounders, they do hold 1 more round so I'm not entirely convinced the springs get compressed less. But if that's the case, it might explain why the 7 round mags had problems with the old springs, while the 6 round mags didn't.

As you would expect, no failures with the 6 round mags this time either.

Thanks for the input, folks.